Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua, Rafael Bustillo Province, Potosi Department, Bolivia
Thumbnail, 2.9 x 1.7 x 1.2 cm
Monazite gets its name from the Greek word "monazein," which means "to be alone," in allusion to its isolated crystals and their rarity when first found. Monazite is usually found in granitic pegmatites, but these crystals are found in hydrothermal tin veins where there is an absolute absence of Lanthanum (usually a trace element in Monazite). This is a fine specimen hosting very-well crystallized, sharp, lustrous, translucent, orange-pink, "butterfly" twinned crystals of Monazite-Ce measuring 7 mm on Quartz crystals on matrix. The crystals actually perform a color change in different lighting ranging from orange-pink to almost yellow/colorless depending upon the light source. This piece is from the same mine from which this material was discovered along the Contacto and San Jose veins in this mine and was first described by Sam Gordon and Mark Bandy.